Summary of Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and ConsolidationThe accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”). Certain changes in presentation were made in the consolidated financial statements for the year ended December 31, 2019 and 2018, to conform to the presentation for the year ended December 31, 2020
Consolidation	The consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries and its majority-owned subsidiary. The portion of equity not attributable to the Company is considered non-controlling interest and is classified separately in the consolidated financial statements. Any subsequent changes in the Company’s ownership interest while the Company retains its controlling interest in its majority-owned subsidiary will be accounted for as equity transactions. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities and equity accounts; disclosure of contingent assets and liabilities at the date of the financial statements; and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to marketable investments, allowances for credit losses, standalone selling prices used to allocate revenue to performance obligations which are not directly observable, the amount of variable consideration included in the transaction price, warranty reserve, valuation of inventories, useful lives of property and equipment, operating and finance lease right-of-use (“ROU”) assets and liabilities, income taxes, contingent consideration and other contingencies, among others. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other data. Actual results could differ from those estimates.
Segments	Segments The Company determined its operating segment on the same basis that it uses to evaluate its performance internally. The Company has one business activity: the design, development, manufacturing and marketing of innovative medical devices, and operates as one operating segment. The Company’s chief operating decision-maker (“CODM”), its Chief Executive Officer, reviews its consolidated operating results for the purpose of allocating resources and evaluating financial performance.
Foreign Currency Translation	Foreign Currency Translation The Company’s consolidated financial statements are prepared in United States Dollars (“USD”). Its foreign subsidiaries use their local currency as their functional currency and maintain their records in the local currency. Accordingly, the assets and liabilities of these subsidiaries are translated into USD using the current exchange rates in effect at the balance sheet date and equity accounts are translated into USD using historical rates. Revenues are translated using the exchange rate as of the date of transaction and expenses are translated using the average exchange rates in effect for the year involved. The resulting foreign currency translation adjustments are recorded in accumulated other comprehensive income (loss) in the consolidated balance sheets. Transactions denominated in currencies other than the respective functional currencies are translated at exchange rates as of the date of transaction with foreign currency gains and losses recorded in other expense, net in the consolidated statements of operations. The Company realized net foreign currency transaction losses of a nominal amount, $0.8 million and $0.9 million during the years ended December 31, 2020, 2019 and 2018, respectively. As the Company’s international operations grow, its risks associated with fluctuation in currency rates will become greater, and the Company will continue to reassess its approach to managing this risk. In addition, currency fluctuations or a weakening USD can increase the costs of the Company’s international expansion. To date, the Company has not entered into any foreign currency hedging contracts.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents, marketable investments (as described in greater detail in this footnote under the header “Cash, Cash Equivalents and Marketable Investments” below) and accounts receivable. The majority of the Company’s cash is held by one financial institution in the U.S. in excess of federally insured limits. The Company maintained investments in money market funds that were not federally insured during the year ended December 31, 2020 and held cash in foreign entities of approximately $17.4 million and $17.3 million at December 31, 2020 and 2019, respectively, which was not federally insured. The Company’s revenue has been derived from sales of its products in the United States and international markets. The Company uses both its own salesforce and independent distributors to sell its products. Concentrations of credit risk with respect to accounts receivable are limited due to the large number of entities comprising the Company’s customer base. The Company performs ongoing credit evaluations of its customers, including its distributors, does not require collateral, and maintains allowances for potential credit losses on customer accounts when deemed necessary.
Significant Risks and Uncertainties	Significant Risks and Uncertainties The Company is subject to risks common to medical device companies including, but not limited to, new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, product liability, uncertainty of market acceptance of products and the potential need to obtain additional financing. The Company is dependent on third party suppliers, in some cases single-source suppliers. There can be no assurance that the Company’s products will continue to be accepted in the marketplace, nor can there be any assurance that any future products can be developed or manufactured at an acceptable cost and with appropriate performance characteristics, or that such products will be successfully marketed, if at all. The Company’s products require approval or clearance from the FDA prior to commencing commercial sales in the United States. There can be no assurance that the Company’s products will receive all of the required approvals or clearances. Approvals or clearances are also required in foreign jurisdictions in which the Company sells its products. If the Company is denied such approvals or clearances or such approvals or clearances are delayed, it may have a material adverse impact on the Company’s results of operations, financial position and liquidity.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Carrying amounts of certain of the Company’s financial instruments, including cash equivalents, accounts receivable, prepaid expenses and other current assets, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities.
Cash and Cash Equivalents	Cash, Cash Equivalents and Marketable Investments The Company invests its cash primarily in highly liquid corporate debt securities, debt instruments of U.S. federal, state and municipal governments, and their agencies, in money market funds and in commercial paper. All highly liquid investments with stated maturities of three months or less from the date of purchase are classified as cash equivalents; all highly liquid investments with stated maturities of greater than three months are classified as marketable investments. The majority of the Company’s cash and investments are held in U.S. banks.
Marketable Investments	The Company determines the appropriate classification of its investments in marketable investments at the time of purchase and re-evaluates such designation at each balance sheet date. The Company’s marketable investments have been classified and accounted for as available-for-sale. Investments with remaining maturities of more than one year are viewed by the Company as available to support current operations and are classified as current assets under the caption marketable investments in the accompanying consolidated balance sheets. Investments in marketable investments are carried at fair value, with the unrealized gains and losses reported as a component of accumulated other comprehensive loss. Any realized gains or losses on the sale of marketable investments are determined on a specific identification method, and such gains and losses are reflected as a component of other income (expense), net. Impairment of Marketable Investments As a result of the of the adoption of the ASU 2016-13 during the year ended December 31, 2020, the Company is exposed to credit losses through its investments in available-for-sale securities. An investment is impaired if the fair value of the investment is less than its amortized cost basis. The Company reviews each impaired available-for-sale security held in its portfolio to determine whether the decline in fair value below its amortized cost basis is the result of credit losses or other factors. An allowance for credit losses is to be recorded as a charge to net income in an amount equal to the difference between the impaired security’s amortized cost basis and the amount expected to be collected over the lifetime of security, limited by the amount that the fair value is less than its amortized cost basis. Any remaining difference between its amortized cost basis and fair value is deemed not to be due to expected credit losses and is recorded as a component of accumulated other comprehensive loss. The Company’s impairment review considers several factors to determine if an expected credit loss is present including the discounted present value of expected cash flows of the security, the capacity to hold a security or sell a security before recovery of the decline in amortized cost, the credit rating of the security and forecasted and historical factors that affect the value of the security. In fiscal years prior to the adoption of ASU 2016-13, unrealized gains or losses on these securities were recorded to accumulated other comprehensive loss until either the security was sold or the Company determined that the decline in value was other-than-temporary. The primary differentiating factors the Company considered when classifying impairments as either temporary or other-than-temporary impairments was the intent and ability to retain the investment in the issuer for a period of time sufficient to allow for any anticipated recovery in market value, the length of the time and the extent to which the market value of the investment had been less than cost, the financial condition, and near-term prospects of the issuer.
Non-Marketable Equity Investments	Non-Marketable Equity InvestmentsEntities in which the Company has at least a 20%, but not more than a 50%, interest are accounted for under the equity method unless it is determined that the Company has a controlling financial interest in the entity, in which case the entity would be consolidated. Non-marketable equity investments are classified as long-term investments on the consolidated balance sheet. The Company’s proportionate share of the operating results of its non-marketable equity method investments are recorded as profit or loss and presented in equity in losses of unconsolidated investee, in the consolidated statements of operations.
Accounts Receivable	Accounts Receivable As a result of the adoption of ASU 2016-13 on January 1, 2020, accounts receivable are measured at amortized cost less the allowance for credit losses. The Company measures expected credit losses for its accounts receivables utilizing a loss-rate approach. The allowance for expected credit losses assessment requires a degree of estimation and judgement. The expected loss-rate is calculated by utilizing historical credit losses incurred as a percentage of the Company’s historical accounts receivable balances, pooled by customers with similar geographic credit risk characteristics. The loss-rate is adjusted for management’s expectations regarding current conditions and forecasts about future conditions which impact expected credit losses. The Company considers factors such as customers credit risk, geographic related risks and economic conditions that may affect a customer’s credit quality classification. Prior to the adoption of ASU 2016-13, the Company recognized losses when a loss was incurred or deemed probable by recording a specific allowance against amounts due, and thereby reducing the net recognized receivable to the amount reasonably believed to be collectible. In fiscal years prior to the adoption of ASU 2016-13, accounts receivable were stated at invoice value less estimated allowances for doubtful accounts. The Company recognized losses when a loss was incurred or deemed probable by recording a specific allowance against amounts due, and thereby reducing the net recognized receivable to the amount reasonably believed to be collectible. The Company monitored customer payments and maintained a reserve for estimated losses resulting from its customers’ inability to make required payments considering factors such as historical experience, credit quality, age of the accounts receivable balances, geographic related risks and economic conditions that may affect a customer’s ability to pay.
Inventories	Inventories Inventories are stated at the lower of cost (determined under the first-in first-out method) or net realizable value. Write-downs are provided for raw materials, components or finished goods that are determined to be excessive or obsolete. The Company regularly reviews inventory quantities in consideration of actual loss experience, projected future demand and remaining shelf life to record a provision for excess and obsolete inventory when appropriate.
Property and Equipment, net	Property and Equipment, net Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized using the straight-line method over the shorter of the lease term or estimated useful life. Machinery and equipment and furniture and fixtures are depreciated over a five to ten year period and computers and software are depreciated over two to five years. Upon retirement or sale, the cost and the related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is reflected in operations. Maintenance and repairs are charged to consolidated statements of operations as incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. When such an event occurs, management determines whether there has been impairment by comparing the anticipated undiscounted future net cash flows to the related asset group’s carrying value. If an asset is considered impaired, the asset is written down to fair value, which is determined based either on discounted cash flows or appraised value, depending on the nature of the asset.
Contingent Consideration	Contingent Consideration Certain agreements the Company enters into involve the potential payment of future consideration that is contingent upon certain performance and revenue milestones being achieved. Contingent consideration obligations incurred in connection with a business combination are recorded at their fair values on the acquisition date and remeasured at their fair values each subsequent reporting period until the related contingencies are resolved. The resulting changes in fair values are recognized generally within sales, general and administrative expense, depending on the nature of the contingent consideration liability, in the consolidated statements of operations. Asset acquisitions are accounted for using a cost accumulation and allocation model and the cost of the acquisition is allocated to the assets acquired and liabilities assumed. Contingent consideration obligations incurred in connection with an asset acquisition are recorded when it is probable that they will occur and they can be reasonably estimated.
Intangible Assets	Intangible Assets Intangible assets primarily consist of purchased rights to licensed technology, customer relationships, and trade secrets and processes. Indefinite-lived intangible assets consisted of an exclusive right to licensed technology. The acquired licensed technology was accounted for as an indefinite-lived intangible asset. Indefinite-lived intangible assets are tested for impairment at least annually, in the fourth quarter, or more frequently if events or circumstances indicate that it is more likely than not that the asset is impaired. If the fair value of the asset is less than the carrying amount, an impairment loss would be recognized in an amount equal to the difference between the carrying amount and the fair value. Refer to Note “7. Intangible Assets” for more information on the Company’s intangible assets. Finite-lived intangible assets are amortized over the estimated economic useful lives of the assets, which is the period during which expected cash flows support the fair value of such intangible assets. The Company reviews finite-lived intangible assets for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets or asset group may not be recoverable. When such an event occurs, management determines whether there has been impairment by comparing the anticipated undiscounted future net cash flows to the related asset group’s carrying value. Refer to Note “7. Intangible Assets” for more information on the Company’s intangible assets.
Goodwill	Goodwill Goodwill represents the excess of the purchase price of an acquired business or assets over the fair value of the identifiable assets acquired and liabilities assumed. Goodwill is not amortized, but is tested for impairment annually in the fourth quarter, or more frequently if events or circumstances indicate the carrying value may no longer be recoverable and that an impairment loss may have occurred. The Company operates as one segment, which is considered to be the sole reporting unit, and therefore goodwill is tested for impairment at the consolidated level.
Revenue Recognition	Revenue Recognition Revenue is primarily comprised of product revenue net of returns, discounts, administration fees and sales rebates. The Company adopted the guidance under ASC 606 on January 1, 2018 using the modified retrospective method for all contracts not completed as of the date of adoption. Under ASC 606, the Company recognizes revenue when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. Revenue from product sales is recognized either on the date of shipment or the date of receipt by the customer, but is deferred for certain transactions when control has not yet transferred. With respect to products that the Company consigns to hospitals, which primarily consist of coils, the Company recognizes revenue at the time hospitals utilize products in a procedure. Certain arrangements with customers contain multiple performance obligations. For these contracts, revenue is allocated to each performance obligation based on its relative standalone selling price. Standalone selling prices are based on observable prices at which the Company separately sells the products or services. If a standalone selling price is not directly observable, then the Company estimates the standalone selling prices considering entity-specific factors including, but not limited to, the expected cost and margin of the products and services, geographies, and other market conditions. The use of alternative estimates could result in a different amount of revenue deferral. Deferred revenue represents amounts that the Company has already invoiced and are ultimately expected to be recognized as revenue, but for which not all revenue recognition criteria have been met. As of December 31, 2020 and December 31, 2019, respectively, the Company's deferred revenue balance was not material. Revenue is recorded at the net sales price, which includes estimates of variable consideration such as product returns utilizing historical return rates, rebates, discounts, and other adjustments to net revenue. To the extent the transaction price includes variable consideration, the Company estimates the amount of variable consideration that should be included in the transaction price. Variable consideration is included in revenue only to the extent that it is probable that a significant reversal of the revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The Company’s terms and conditions permit product returns and exchanges. The Company bases its estimates for sales returns on actual historical returns over the prior three years and they are recorded as reductions in revenue at the time of sale. Upon recognition, the Company reduces revenue and cost of revenue for the estimated return. Return rates can fluctuate over time, but are sufficiently predictable to allow the Company to estimate expected future product returns.
Shipping Costs	Shipping Costs Shipping and handling costs charged to customers are recorded as revenue. Shipping and handling costs are included in cost of revenue.
Research and Development (R&D) Costs	Research and Development (“R&D”) Costs R&D costs primarily consist of product development, clinical and regulatory expenses, materials, depreciation and other costs associated with the development of the Company’s products. R&D costs also include related personnel and consultants’ salaries, benefits and related costs, including stock-based compensation. The Company expenses R&D costs as they are incurred. The Company’s clinical trial accruals are based on estimates of patient enrollment and related costs at clinical investigator sites. The Company estimates preclinical and clinical trial expenses based on the services performed pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on its behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of patient enrollment and activity expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Payments made to third parties under these arrangements in advance of the receipt of the related services are recorded as prepaid expenses until the services are rendered. Internal Use Software The Company capitalizes certain costs incurred for the development of computer software for internal use. These costs generally relate to third-party software as well as the internal development of software associated with our REAL Immersive System offerings. The Company capitalizes these costs when it is determined that it is probable that the project will be completed and the software will be used to perform the function intended, and the preliminary project stage is completed. Capitalized internal use software development costs are included in Property and equipment, net within the consolidated balance sheets. Capitalized internal use software is amortized on a straight-line basis over its estimated useful life. For software that supports our REAL Immersive System, the amortization expense is recorded in cost of revenue within the consolidated statements of operations. Costs related to the preliminary project stage, post-implementation, training and maintenance are expensed as incurred.
Advertising Costs	Advertising CostsAdvertising costs are included in sales, general and administrative expenses and are expensed as incurred.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes the cost of stock-based compensation in the financial statements based upon fair value. The fair value of restricted stock and restricted stock unit (“RSU”) awards is determined based on the number of units granted and the closing price of the Company’s common stock as of the grant date. The fair value of each purchase under the employee stock purchase plan (“ESPP”) is estimated at the beginning of the offering period using the Black-Scholes option pricing model. The fair value of stock options is determined as of the grant date using the Black-Scholes option pricing model. The Company’s determination of the fair value of equity-settled awards is impacted by the price of the Company’s common stock as well as changes in assumptions regarding a number of complex and subjective variables. These variables include, but are not limited to, the expected term that awards will remain outstanding, expected common stock price volatility over the term of the awards, risk-free interest rates and expected dividends. The fair value of an award is recognized over the requisite service period (usually the vesting period) on a straight-line basis. Stock-based compensation expense recognized at fair value includes the impact of estimated forfeitures. The Company estimates future forfeitures at the date of grant and revises the estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates. To the extent actual forfeiture results differ from the estimates, the difference is recorded as a cumulative adjustment in the period forfeiture estimates are revised. No compensation cost is recorded for awards that do not vest. Prior to the adoption of Accounting Standard Update (“ASU”) No. 2018-07, “Compensation – Stock Compensation,” the Company recorded its equity instruments issued to non-employees at their fair value on the measurement date and were subject to periodic adjustments as the Company remeasured the fair value of the non-employee awards at each reporting period prior to vesting and at the vesting dates of each non-employee award. In the third quarter of 2018, the Company adopted ASU 2018-07 and recognizes the fair value of non-employee awards over the requisite service period (usually the vesting period) on a straight-line basis. Therefore, equity instruments issued to non-employees are recorded at their fair value on the grant date in the same manner as employee awards. The fair value of these equity instruments is expensed over the service period. Estimates of the fair value of equity-settled awards as of the grant date using valuation models, such as the Black-Scholes option pricing model, are affected by assumptions regarding a number of complex variables. Changes in the assumptions can materially affect the fair value of the award and ultimately how much stock-based compensation expense is recognized. These inputs are subjective and generally require significant analysis and judgment to develop. For all stock options granted prior to the Company’s IPO, the Company estimated the volatility data based on a study of publicly traded industry peer companies. For purposes of identifying these peer companies, the Company considered the industry, stage of development, size and financial leverage of potential comparable companies. The risk-free interest rate is based on the yield available on U.S. Treasury zero-coupon issues similar in duration to the expected term of the equity-settled award. For all stock options granted prior to the IPO, the Company used the Staff Accounting Bulletin, No. 110 (“SAB 110”) simplified method to calculate the expected term, which is the average of the contractual term and vesting period. For stock options granted post-IPO, the Company used its historical data to calculate the expected term and volatility used in the valuation of options.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method, whereby deferred tax asset (“DTA”) and liability account balances are determined based on differences between the financial reporting and tax bases of assets and liabilities, and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company provides a valuation allowance to reduce the net DTAs to their estimated realizable value. The calculation of the Company’s current provision for income taxes involves the use of estimates, assumptions and judgments while taking into account current tax laws, interpretation of current tax laws and possible outcomes of future tax audits. The Company has established reserves to address potential exposures related to tax positions that could be challenged by tax authorities. Although the Company believes its estimates, assumptions and judgments to be reasonable, any changes in tax law or its interpretation of tax laws and the resolutions of potential tax audits could significantly impact the amounts provided for income taxes in the Company’s consolidated financial statements. The calculation of the Company’s DTA balance involves the use of estimates, assumptions and judgments while taking into account estimates of the amounts and type of future taxable income. Actual future operating results and the underlying amount and type of income could differ materially from the Company’s estimates, assumptions and judgments thereby impacting the Company’s financial position and results of operations. The Company follows the guidance relating to accounting for uncertainty in income taxes, which prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of uncertain tax positions taken or expected to be taken in the Company’s income tax return, and also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods and disclosure. The Company includes interest and penalties related to unrecognized tax benefits within income tax expense in the accompanying consolidated statements of operations.
Comprehensive Income	Comprehensive Income Comprehensive income consists of net income, unrealized gains or losses on available-for-sale investments and the effects of foreign currency translation adjustments. The Company presents comprehensive income and its components in the consolidated statements of comprehensive (loss) income.
Net (Loss) Income Per Share of Common Stock	Net (Loss) Income Per Share of Common Stock The Company’s basic net (loss) income attributable to Penumbra, Inc. per share is calculated by dividing the net (loss) income attributable to Penumbra, Inc. per share by the weighted average number of shares of common stock outstanding for the period. The diluted net (loss) income per share attributable to Penumbra, Inc. is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period. For purposes of this calculation, options to purchase common stock, restricted stock and restricted stock units are considered common stock equivalents.
Leases	Leases The Company adopted the guidance under ASC Topic 842, “Leases” ("ASC 842") on January 1, 2019 using the modified retrospective transition approach. There was no cumulative-effect adjustment recorded to retained earnings upon adoption. Under ASC 842, the Company determines if an arrangement is a lease at inception. In addition, the Company determines whether leases meet the classification criteria of a finance or operating lease at the lease commencement date considering: (1) whether the lease transfers ownership of the underlying asset to the lessee at the end of the lease term, (2) whether the lease contains a bargain purchase option, (3) whether the lease term is for a major part of the remaining economic life of the underlying asset, (4) whether the present value of the sum of the lease payments and residual value guaranteed by the lessee equals or exceeds substantially all of the fair value of the underlying asset, and (5) whether the underlying asset is of such a specialized nature that it is expected to have no alternative use to the lessor at the end of the lease term. As of December 31, 2020, the Company's lease population consisted of operating and finance real estate, equipment and vehicle leases. Operating leases are included in operating lease right-of-use assets, current operating lease liabilities, and non-current operating lease liabilities in our consolidated balance sheet. Finance leases are included in finance lease right-of-use assets, current finance lease liabilities, and non-current finance lease liabilities in our consolidated balance sheet. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Lease ROU assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the present value of lease payments, the Company uses its incremental borrowing rate which requires management’s judgement as the rate implicit in the lease is generally not readily determinable. The determination of the Company’s incremental borrowing rate requires management judgment including, the development of a synthetic credit rating and cost of debt as the Company currently does not carry any debt. The operating lease ROU assets also include adjustments for prepayments, accrued lease payments and exclude lease incentives. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise such options. Operating lease cost is recognized on a straight-line basis over the expected lease term. Finance lease cost is recognized as depreciation expense on a straight-line basis over the expected lease term and interest expense using the accelerated interest method of recognition. Lease agreements entered into after the adoption of ASC 842 that include lease and non-lease components are accounted for as a single lease component. Lease agreements with a non-cancelable term of less than 12 months are not recorded on the Company’s consolidated balance sheet.
Recent Accounting Guidance and Recently Issued Accounting Standards	Recent Accounting Guidance Recently Adopted Accounting Standards On January 1, 2020, the Company adopted ASU No. 2016-13, Financial Instruments—Credit Losses (“ASU 2016-13”) using the modified retrospective transition approach, with the impact upon adoption reflected in opening retained earnings. The comparative prior year information has not been adjusted and continues to be reported under legacy GAAP. The standard significantly changed the impairment model for most financial assets and certain other instruments, including accounts receivable and available-for-sale securities. For financial assets measured at amortized cost, including our accounts receivable, the standard requires an entity to (1) estimate its lifetime expected credit losses upon recognition of the financial assets and establish an allowance to present the net amount expected to be collected, (2) recognize this allowance and changes in the allowance during subsequent periods through net income and (3) consider relevant information about past events, current conditions and reasonable and supportable forecasts in assessing the lifetime expected credit losses. For available-for-sale debt securities, this standard made several targeted amendments to the existing other-than-temporary impairment model, including (1) requiring disclosure of the allowance for credit losses, (2) allowing reversals of the previously recognized credit losses until the entity has the intent to sell, is more-likely-than-not required to sell the securities or the maturity of the securities, (3) limiting impairment to the difference between the amortized cost basis and fair value and (4) not allowing entities to consider the length of time that fair value has been less than amortized cost as a factor in evaluating whether a credit loss exists. As a result of adoption, the cumulative impact related to accounts receivable expected credit losses to our opening retained earnings at January 1, 2020 was $1.2 million. As of the adoption date, the difference between the amortized cost basis and fair value of the Company’s impaired available-for-sale securities held was not material. Accordingly, upon adoption there was no impact to our opening retained earnings for credit losses related to available-for-sale securities. For additional information on the impact of the adoption and disclosures required by ASU 2016-13, refer to Note “3. Investments and Fair Value of Financial Instruments” and Note “4. Balance Sheet Components.” On January 1, 2020, the Company adopted ASU 2018-13, Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. The primary focus of the standard is to improve the effectiveness of the disclosure requirements for fair value measurements. The Company had no significant changes to the fair value measurement related disclosures due to the adoption of the standard. Recently Issued Accounting Standards In December 2019, the FASB issued ASU No. 2019-12, Income Taxes— Simplifying the Accounting for Income Taxes. The standard intends to simplify and reduce the cost of accounting for income taxes. The new guidance removes certain exceptions for recognizing deferred taxes for foreign investments, the incremental approach to performing intraperiod allocation, and calculating income taxes in interim periods for year to date losses that exceed anticipated full year losses. The standard also adds guidance to reduce complexity in certain areas, including accounting for franchise taxes that are partially based on income, transactions with a government that result with a step up in the tax basis of goodwill, enacted changes in tax law during interim periods, and allocating taxes to members of a consolidated group which are not subject to tax. For public business entities, the amendments in ASU 2019-12 are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted for all periods in which financial statements have not yet been issued, including interim periods. The Company does not expect the adoption of this standard will have a material impact on its consolidated financial statements and does not elect to early adopt as of December 31, 2020.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Basis of Presentation and ConsolidationThe accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”). Certain changes in presentation were made in the consolidated financial statements for the year ended December 31, 2019 and 2018, to conform to the presentation for the year ended December 31, 2020

Consolidation

The consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries and its majority-owned subsidiary. The portion of equity not attributable to the Company is considered non-controlling interest and is classified separately in the consolidated financial statements. Any subsequent changes in the Company’s ownership interest while the Company retains its controlling interest in its majority-owned subsidiary will be accounted for as equity transactions. All intercompany balances and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities and equity accounts; disclosure of contingent assets and liabilities at the date of the financial statements; and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to marketable investments, allowances for credit losses, standalone selling prices used to allocate revenue to performance obligations which are not directly observable, the amount of variable consideration included in the transaction price, warranty reserve, valuation of inventories, useful lives of property and equipment, operating and finance lease right-of-use (“ROU”) assets and liabilities, income taxes, contingent consideration and other contingencies, among others. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other data. Actual results could differ from those estimates.

Segments

Segments The Company determined its operating segment on the same basis that it uses to evaluate its performance internally. The Company has one business activity: the design, development, manufacturing and marketing of innovative medical devices, and operates as one operating segment. The Company’s chief operating decision-maker (“CODM”), its Chief Executive Officer, reviews its consolidated operating results for the purpose of allocating resources and evaluating financial performance.

Foreign Currency Translation

The Company’s consolidated financial statements are prepared in United States Dollars (“USD”). Its foreign subsidiaries use their local currency as their functional currency and maintain their records in the local currency. Accordingly, the assets and liabilities of these subsidiaries are translated into USD using the current exchange rates in effect at the balance sheet date and equity accounts are translated into USD using historical rates. Revenues are translated using the exchange rate as of the date of transaction and expenses are translated using the average exchange rates in effect for the year involved. The resulting foreign currency translation adjustments are recorded in accumulated other comprehensive income (loss) in the consolidated balance sheets. Transactions denominated in currencies other than the respective functional currencies are translated at exchange rates as of the date of transaction with foreign currency gains and losses recorded in other expense, net in the consolidated statements of operations. The Company realized net foreign currency transaction losses of a nominal amount, $0.8 million and $0.9 million during the years ended December 31, 2020, 2019 and 2018, respectively.

As the Company’s international operations grow, its risks associated with fluctuation in currency rates will become greater, and the Company will continue to reassess its approach to managing this risk. In addition, currency fluctuations or a weakening USD can increase the costs of the Company’s international expansion. To date, the Company has not entered into any foreign currency hedging contracts.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents, marketable investments (as described in greater detail in this footnote under the header “Cash, Cash Equivalents and Marketable Investments” below) and accounts receivable. The majority of the Company’s cash is held by one financial institution in the U.S. in excess of federally insured limits. The Company maintained investments in money market funds that were not federally insured during the year ended December 31, 2020 and held cash in foreign entities of approximately $17.4 million and $17.3 million at December 31, 2020 and 2019, respectively, which was not federally insured.

The Company’s revenue has been derived from sales of its products in the United States and international markets. The Company uses both its own salesforce and independent distributors to sell its products. Concentrations of credit risk with respect to accounts receivable are limited due to the large number of entities comprising the Company’s customer base. The Company performs ongoing credit evaluations of its customers, including its distributors, does not require collateral, and maintains allowances for potential credit losses on customer accounts when deemed necessary.

Significant Risks and Uncertainties

The Company is subject to risks common to medical device companies including, but not limited to, new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, product liability, uncertainty of market acceptance of products and the potential need to obtain additional financing. The Company is dependent on third party suppliers, in some cases single-source suppliers.

There can be no assurance that the Company’s products will continue to be accepted in the marketplace, nor can there be any assurance that any future products can be developed or manufactured at an acceptable cost and with appropriate performance characteristics, or that such products will be successfully marketed, if at all.

The Company’s products require approval or clearance from the FDA prior to commencing commercial sales in the United States. There can be no assurance that the Company’s products will receive all of the required approvals or clearances. Approvals or clearances are also required in foreign jurisdictions in which the Company sells its products. If the Company is denied such approvals or clearances or such approvals or clearances are delayed, it may have a material adverse impact on the Company’s results of operations, financial position and liquidity.

Fair Value of Financial Instruments

Fair Value of Financial Instruments Carrying amounts of certain of the Company’s financial instruments, including cash equivalents, accounts receivable, prepaid expenses and other current assets, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities.

Cash and Cash Equivalents

Cash, Cash Equivalents and Marketable Investments The Company invests its cash primarily in highly liquid corporate debt securities, debt instruments of U.S. federal, state and municipal governments, and their agencies, in money market funds and in commercial paper. All highly liquid investments with stated maturities of three months or less from the date of purchase are classified as cash equivalents; all highly liquid investments with stated maturities of greater than three months are classified as marketable investments. The majority of the Company’s cash and investments are held in U.S. banks.

Marketable Investments

The Company determines the appropriate classification of its investments in marketable investments at the time of purchase and re-evaluates such designation at each balance sheet date. The Company’s marketable investments have been classified and accounted for as available-for-sale. Investments with remaining maturities of more than one year are viewed by the Company as available to support current operations and are classified as current assets under the caption marketable investments in the accompanying consolidated balance sheets. Investments in marketable investments are carried at fair value, with the unrealized gains and losses reported as a component of accumulated other comprehensive loss. Any realized gains or losses on the sale of marketable investments are determined on a specific identification method, and such gains and losses are reflected as a component of other income (expense), net.

Impairment of Marketable Investments

As a result of the of the adoption of the ASU 2016-13 during the year ended December 31, 2020, the Company is exposed to credit losses through its investments in available-for-sale securities. An investment is impaired if the fair value of the investment is less than its amortized cost basis. The Company reviews each impaired available-for-sale security held in its portfolio to determine whether the decline in fair value below its amortized cost basis is the result of credit losses or other factors. An allowance for credit losses is to be recorded as a charge to net income in an amount equal to the difference between the impaired security’s amortized cost basis and the amount expected to be collected over the lifetime of security, limited by the amount that the fair value is less than its amortized cost basis. Any remaining difference between its amortized cost basis and fair value is deemed not to be due to expected credit losses and is recorded as a component of accumulated other comprehensive loss. The Company’s impairment review considers several factors to determine if an expected credit loss is present including the discounted present value of expected cash flows of the security, the capacity to hold a security or sell a security before recovery of the decline in amortized cost, the credit rating of the security and forecasted and historical factors that affect the value of the security.

In fiscal years prior to the adoption of ASU 2016-13, unrealized gains or losses on these securities were recorded to accumulated other comprehensive loss until either the security was sold or the Company determined that the decline in value was other-than-temporary. The primary differentiating factors the Company considered when classifying impairments as either temporary or other-than-temporary impairments was the intent and ability to retain the investment in the issuer for a period of time sufficient to allow for any anticipated recovery in market value, the length of the time and the extent to which the market value of the investment had been less than cost, the financial condition, and near-term prospects of the issuer.

Non-Marketable Equity Investments

Non-Marketable Equity InvestmentsEntities in which the Company has at least a 20%, but not more than a 50%, interest are accounted for under the equity method unless it is determined that the Company has a controlling financial interest in the entity, in which case the entity would be consolidated. Non-marketable equity investments are classified as long-term investments on the consolidated balance sheet. The Company’s proportionate share of the operating results of its non-marketable equity method investments are recorded as profit or loss and presented in equity in losses of unconsolidated investee, in the consolidated statements of operations.

Accounts Receivable

As a result of the adoption of ASU 2016-13 on January 1, 2020, accounts receivable are measured at amortized cost less the allowance for credit losses. The Company measures expected credit losses for its accounts receivables utilizing a loss-rate approach. The allowance for expected credit losses assessment requires a degree of estimation and judgement. The expected loss-rate is calculated by utilizing historical credit losses incurred as a percentage of the Company’s historical accounts receivable balances, pooled by customers with similar geographic credit risk characteristics. The loss-rate is adjusted for management’s expectations regarding current conditions and forecasts about future conditions which impact expected credit losses. The Company considers factors such as customers credit risk, geographic related risks and economic conditions that may affect a customer’s credit quality classification.

Prior to the adoption of ASU 2016-13, the Company recognized losses when a loss was incurred or deemed probable by recording a specific allowance against amounts due, and thereby reducing the net recognized receivable to the amount reasonably believed to be collectible. In fiscal years prior to the adoption of ASU 2016-13, accounts receivable were stated at invoice value less estimated allowances for doubtful accounts. The Company recognized losses when a loss was incurred or deemed probable by recording a specific allowance against amounts due, and thereby reducing the net recognized receivable to the amount reasonably believed to be collectible. The Company monitored customer payments and maintained a reserve for estimated losses resulting from its customers’ inability to make required payments considering factors such as historical experience, credit quality, age of the accounts receivable balances, geographic related risks and economic conditions that may affect a customer’s ability to pay.

Inventories

Inventories Inventories are stated at the lower of cost (determined under the first-in first-out method) or net realizable value. Write-downs are provided for raw materials, components or finished goods that are determined to be excessive or obsolete. The Company regularly reviews inventory quantities in consideration of actual loss experience, projected future demand and remaining shelf life to record a provision for excess and obsolete inventory when appropriate.

Property and Equipment, net

Property and Equipment, net Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized using the straight-line method over the shorter of the lease term or estimated useful life. Machinery and equipment and furniture and fixtures are depreciated over a five to ten year period and computers and software are depreciated over two to five years. Upon retirement or sale, the cost and the related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is reflected in operations. Maintenance and repairs are charged to consolidated statements of operations as incurred.

Impairment of Long-Lived Assets

Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. When such an event occurs, management determines whether there has been impairment by comparing the anticipated undiscounted future net cash flows to the related asset group’s carrying value. If an asset is considered impaired, the asset is written down to fair value, which is determined based either on discounted cash flows or appraised value, depending on the nature of the asset.

Contingent Consideration

Certain agreements the Company enters into involve the potential payment of future consideration that is contingent upon certain performance and revenue milestones being achieved. Contingent consideration obligations incurred in connection with a business combination are recorded at their fair values on the acquisition date and remeasured at their fair values each subsequent reporting period until the related contingencies are resolved. The resulting changes in fair values are recognized generally within sales, general and administrative expense, depending on the nature of the contingent consideration liability, in the consolidated statements of operations. Asset acquisitions are accounted for using a cost accumulation and allocation model and the cost of the acquisition is allocated to the assets acquired and liabilities assumed. Contingent consideration obligations incurred in connection with an asset acquisition are recorded when it is probable that they will occur and they can be reasonably estimated.

Intangible Assets

Intangible assets primarily consist of purchased rights to licensed technology, customer relationships, and trade secrets and processes.

Indefinite-lived intangible assets consisted of an exclusive right to licensed technology. The acquired licensed technology was accounted for as an indefinite-lived intangible asset. Indefinite-lived intangible assets are tested for impairment at least annually, in the fourth quarter, or more frequently if events or circumstances indicate that it is more likely than not that the asset is impaired. If the fair value of the asset is less than the carrying amount, an impairment loss would be recognized in an amount equal to the difference between the carrying amount and the fair value. Refer to Note “7. Intangible Assets” for more information on the Company’s intangible assets.

Finite-lived intangible assets are amortized over the estimated economic useful lives of the assets, which is the period during which expected cash flows support the fair value of such intangible assets. The Company reviews finite-lived intangible assets for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets or asset group may not be recoverable. When such an event occurs, management determines whether there has been impairment by comparing the anticipated undiscounted future net cash flows to the related asset group’s carrying value. Refer to Note “7. Intangible Assets” for more information on the Company’s intangible assets.

Goodwill

Goodwill represents the excess of the purchase price of an acquired business or assets over the fair value of the identifiable assets acquired and liabilities assumed. Goodwill is not amortized, but is tested for impairment annually in the fourth quarter, or

more frequently if events or circumstances indicate the carrying value may no longer be recoverable and that an impairment loss may have occurred. The Company operates as one segment, which is considered to be the sole reporting unit, and therefore goodwill is tested for impairment at the consolidated level.

Revenue Recognition

Revenue is primarily comprised of product revenue net of returns, discounts, administration fees and sales rebates. The Company adopted the guidance under ASC 606 on January 1, 2018 using the modified retrospective method for all contracts not completed as of the date of adoption. Under ASC 606, the Company recognizes revenue when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. Revenue from product sales is recognized either on the date of shipment or the date of receipt by the customer, but is deferred for certain transactions when control has not yet transferred. With respect to products that the Company consigns to hospitals, which primarily consist of coils, the Company recognizes revenue at the time hospitals utilize products in a procedure.

Certain arrangements with customers contain multiple performance obligations. For these contracts, revenue is allocated to each performance obligation based on its relative standalone selling price. Standalone selling prices are based on observable prices at which the Company separately sells the products or services. If a standalone selling price is not directly observable, then the Company estimates the standalone selling prices considering entity-specific factors including, but not limited to, the expected cost and margin of the products and services, geographies, and other market conditions. The use of alternative estimates could result in a different amount of revenue deferral.

Deferred revenue represents amounts that the Company has already invoiced and are ultimately expected to be recognized as revenue, but for which not all revenue recognition criteria have been met. As of December 31, 2020 and December 31, 2019, respectively, the Company's deferred revenue balance was not material.

Revenue is recorded at the net sales price, which includes estimates of variable consideration such as product returns utilizing historical return rates, rebates, discounts, and other adjustments to net revenue. To the extent the transaction price includes variable consideration, the Company estimates the amount of variable consideration that should be included in the transaction price. Variable consideration is included in revenue only to the extent that it is probable that a significant reversal of the revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved.

The Company’s terms and conditions permit product returns and exchanges. The Company bases its estimates for sales returns on actual historical returns over the prior three years and they are recorded as reductions in revenue at the time of sale. Upon recognition, the Company reduces revenue and cost of revenue for the estimated return. Return rates can fluctuate over time, but are sufficiently predictable to allow the Company to estimate expected future product returns.

Shipping Costs

Shipping Costs Shipping and handling costs charged to customers are recorded as revenue. Shipping and handling costs are included in cost of revenue.

Research and Development (R&D) Costs

Research and Development (“R&D”) Costs

R&D costs primarily consist of product development, clinical and regulatory expenses, materials, depreciation and other costs associated with the development of the Company’s products. R&D costs also include related personnel and consultants’ salaries, benefits and related costs, including stock-based compensation. The Company expenses R&D costs as they are incurred.

The Company’s clinical trial accruals are based on estimates of patient enrollment and related costs at clinical investigator sites. The Company estimates preclinical and clinical trial expenses based on the services performed pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on its behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of patient enrollment and activity expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Payments made to third parties under these arrangements in advance of the receipt of the related services are recorded as prepaid expenses until the services are rendered.

Internal Use Software

The Company capitalizes certain costs incurred for the development of computer software for internal use. These costs generally relate to third-party software as well as the internal development of software associated with our REAL Immersive System offerings. The Company capitalizes these costs when it is determined that it is probable that the project will be completed and the software will be used to perform the function intended, and the preliminary project stage is completed. Capitalized internal use software development costs are included in Property and equipment, net within the consolidated balance sheets.

Capitalized internal use software is amortized on a straight-line basis over its estimated useful life. For software that supports our REAL Immersive System, the amortization expense is recorded in cost of revenue within the consolidated statements of operations. Costs related to the preliminary project stage, post-implementation, training and maintenance are expensed as incurred.

Advertising Costs

Advertising CostsAdvertising costs are included in sales, general and administrative expenses and are expensed as incurred.

Stock-Based Compensation

The Company recognizes the cost of stock-based compensation in the financial statements based upon fair value. The fair value of restricted stock and restricted stock unit (“RSU”) awards is determined based on the number of units granted and the closing price of the Company’s common stock as of the grant date. The fair value of each purchase under the employee stock purchase plan (“ESPP”) is estimated at the beginning of the offering period using the Black-Scholes option pricing model. The fair value of stock options is determined as of the grant date using the Black-Scholes option pricing model. The Company’s determination of the fair value of equity-settled awards is impacted by the price of the Company’s common stock as well as changes in assumptions regarding a number of complex and subjective variables. These variables include, but are not limited to, the expected term that awards will remain outstanding, expected common stock price volatility over the term of the awards, risk-free interest rates and expected dividends.

The fair value of an award is recognized over the requisite service period (usually the vesting period) on a straight-line basis. Stock-based compensation expense recognized at fair value includes the impact of estimated forfeitures. The Company estimates future forfeitures at the date of grant and revises the estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates. To the extent actual forfeiture results differ from the estimates, the difference is recorded as a cumulative adjustment in the period forfeiture estimates are revised. No compensation cost is recorded for awards that do not vest.

Prior to the adoption of Accounting Standard Update (“ASU”) No. 2018-07, “Compensation – Stock Compensation,” the Company recorded its equity instruments issued to non-employees at their fair value on the measurement date and were subject to periodic adjustments as the Company remeasured the fair value of the non-employee awards at each reporting period prior to vesting and at the vesting dates of each non-employee award. In the third quarter of 2018, the Company adopted ASU 2018-07 and recognizes the fair value of non-employee awards over the requisite service period (usually the vesting period) on a straight-line basis. Therefore, equity instruments issued to non-employees are recorded at their fair value on the grant date in the same manner as employee awards. The fair value of these equity instruments is expensed over the service period.

Estimates of the fair value of equity-settled awards as of the grant date using valuation models, such as the Black-Scholes option pricing model, are affected by assumptions regarding a number of complex variables. Changes in the assumptions can materially affect the fair value of the award and ultimately how much stock-based compensation expense is recognized. These inputs are subjective and generally require significant analysis and judgment to develop. For all stock options granted prior to the Company’s IPO, the Company estimated the volatility data based on a study of publicly traded industry peer companies. For purposes of identifying these peer companies, the Company considered the industry, stage of development, size and financial leverage of potential comparable companies. The risk-free interest rate is based on the yield available on U.S. Treasury zero-coupon issues similar in duration to the expected term of the equity-settled award. For all stock options granted prior to the IPO, the Company used the Staff Accounting Bulletin, No. 110 (“SAB 110”) simplified method to calculate the expected term, which is the average of the contractual term and vesting period. For stock options granted post-IPO, the Company used its historical data to calculate the expected term and volatility used in the valuation of options.

Income Taxes

The Company accounts for income taxes using the asset and liability method, whereby deferred tax asset (“DTA”) and liability account balances are determined based on differences between the financial reporting and tax bases of assets and liabilities, and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company provides a valuation allowance to reduce the net DTAs to their estimated realizable value.

The calculation of the Company’s current provision for income taxes involves the use of estimates, assumptions and judgments while taking into account current tax laws, interpretation of current tax laws and possible outcomes of future tax audits. The Company has established reserves to address potential exposures related to tax positions that could be challenged by tax authorities. Although the Company believes its estimates, assumptions and judgments to be reasonable, any changes in tax law or its interpretation of tax laws and the resolutions of potential tax audits could significantly impact the amounts provided for income taxes in the Company’s consolidated financial statements.

The calculation of the Company’s DTA balance involves the use of estimates, assumptions and judgments while taking into account estimates of the amounts and type of future taxable income. Actual future operating results and the underlying amount and type of income could differ materially from the Company’s estimates, assumptions and judgments thereby impacting the Company’s financial position and results of operations.

The Company follows the guidance relating to accounting for uncertainty in income taxes, which prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of uncertain tax positions taken or expected to be taken in the Company’s income tax return, and also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods and disclosure.

The Company includes interest and penalties related to unrecognized tax benefits within income tax expense in the accompanying consolidated statements of operations.

Comprehensive Income

Comprehensive Income Comprehensive income consists of net income, unrealized gains or losses on available-for-sale investments and the effects of foreign currency translation adjustments. The Company presents comprehensive income and its components in the consolidated statements of comprehensive (loss) income.

Net (Loss) Income Per Share of Common Stock

The Company’s basic net (loss) income attributable to Penumbra, Inc. per share is calculated by dividing the net (loss) income attributable to Penumbra, Inc. per share by the weighted average number of shares of common stock outstanding for the period. The diluted net (loss) income per share attributable to Penumbra, Inc. is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period. For purposes of this calculation, options to purchase common stock, restricted stock and restricted stock units are considered common stock equivalents.

Leases

The Company adopted the guidance under ASC Topic 842, “Leases” ("ASC 842") on January 1, 2019 using the modified retrospective transition approach. There was no cumulative-effect adjustment recorded to retained earnings upon adoption.

Under ASC 842, the Company determines if an arrangement is a lease at inception. In addition, the Company determines whether leases meet the classification criteria of a finance or operating lease at the lease commencement date considering: (1) whether the lease transfers ownership of the underlying asset to the lessee at the end of the lease term, (2) whether the lease contains a bargain purchase option, (3) whether the lease term is for a major part of the remaining economic life of the underlying asset, (4) whether the present value of the sum of the lease payments and residual value guaranteed by the lessee equals or exceeds substantially all of the fair value of the underlying asset, and (5) whether the underlying asset is of such a specialized nature that it is expected to have no alternative use to the lessor at the end of the lease term. As of December 31, 2020, the Company's lease population consisted of operating and finance real estate, equipment and vehicle leases.

Operating leases are included in operating lease right-of-use assets, current operating lease liabilities, and non-current operating lease liabilities in our consolidated balance sheet. Finance leases are included in finance lease right-of-use assets, current finance lease liabilities, and non-current finance lease liabilities in our consolidated balance sheet. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Lease ROU assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the present value of lease payments, the

Company uses its incremental borrowing rate which requires management’s judgement as the rate implicit in the lease is generally not readily determinable. The determination of the Company’s incremental borrowing rate requires management judgment including, the development of a synthetic credit rating and cost of debt as the Company currently does not carry any debt. The operating lease ROU assets also include adjustments for prepayments, accrued lease payments and exclude lease incentives. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise such options. Operating lease cost is recognized on a straight-line basis over the expected lease term. Finance lease cost is recognized as depreciation expense on a straight-line basis over the expected lease term and interest expense using the accelerated interest method of recognition. Lease agreements entered into after the adoption of ASC 842 that include lease and non-lease components are accounted for as a single lease component. Lease agreements with a non-cancelable term of less than 12 months are not recorded on the Company’s consolidated balance sheet.

Recent Accounting Guidance and Recently Issued Accounting Standards

Recent Accounting Guidance

Recently Adopted Accounting Standards

On January 1, 2020, the Company adopted ASU No. 2016-13, Financial Instruments—Credit Losses (“ASU 2016-13”) using the modified retrospective transition approach, with the impact upon adoption reflected in opening retained earnings. The comparative prior year information has not been adjusted and continues to be reported under legacy GAAP. The standard significantly changed the impairment model for most financial assets and certain other instruments, including accounts receivable and available-for-sale securities.

For financial assets measured at amortized cost, including our accounts receivable, the standard requires an entity to (1) estimate its lifetime expected credit losses upon recognition of the financial assets and establish an allowance to present the net amount expected to be collected, (2) recognize this allowance and changes in the allowance during subsequent periods through net income and (3) consider relevant information about past events, current conditions and reasonable and supportable forecasts in assessing the lifetime expected credit losses.

For available-for-sale debt securities, this standard made several targeted amendments to the existing other-than-temporary impairment model, including (1) requiring disclosure of the allowance for credit losses, (2) allowing reversals of the previously recognized credit losses until the entity has the intent to sell, is more-likely-than-not required to sell the securities or the maturity of the securities, (3) limiting impairment to the difference between the amortized cost basis and fair value and (4) not allowing entities to consider the length of time that fair value has been less than amortized cost as a factor in evaluating whether a credit loss exists.

As a result of adoption, the cumulative impact related to accounts receivable expected credit losses to our opening retained earnings at January 1, 2020 was $1.2 million. As of the adoption date, the difference between the amortized cost basis and fair value of the Company’s impaired available-for-sale securities held was not material. Accordingly, upon adoption there was no impact to our opening retained earnings for credit losses related to available-for-sale securities. For additional information on the impact of the adoption and disclosures required by ASU 2016-13, refer to Note “3. Investments and Fair Value of Financial Instruments” and Note “4. Balance Sheet Components.”

On January 1, 2020, the Company adopted ASU 2018-13, Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. The primary focus of the standard is to improve the effectiveness of the disclosure requirements for fair value measurements. The Company had no significant changes to the fair value measurement related disclosures due to the adoption of the standard.

Recently Issued Accounting Standards

In December 2019, the FASB issued ASU No. 2019-12, Income Taxes— Simplifying the Accounting for Income Taxes. The standard intends to simplify and reduce the cost of accounting for income taxes. The new guidance removes certain exceptions for recognizing deferred taxes for foreign investments, the incremental approach to performing intraperiod allocation, and calculating income taxes in interim periods for year to date losses that exceed anticipated full year losses. The standard also adds guidance to reduce complexity in certain areas, including accounting for franchise taxes that are partially based on income, transactions with a government that result with a step up in the tax basis of goodwill, enacted changes in tax law during interim periods, and allocating taxes to members of a consolidated group which are not subject to tax. For public business entities, the amendments in ASU 2019-12 are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted for all periods in which financial statements have not yet been issued, including interim periods. The Company does not expect the adoption of this standard will have a material impact on its consolidated financial statements and does not elect to early adopt as of December 31, 2020.